After more than 30 years in space heading away from Earth, Pioneer 10 has sent its last signal home.

The distant emissary, over 12 billion kilometres away, will now disappear into the galaxy.

Pioneer's last, very weak signal was received on 22 January, after which US space agency (NASA) engineers reported that its power source had decayed such that it might not be capable of sending another message.

Because of this, NASA has said it has no further plans to contact Pioneer 10.